The invention provides a method and a system for dividing a scheduling period of a power distribution network. The method comprises the steps of S1, acquiring load data of n nodes in the power distribution network within a specified scheduling period; S2, calculating fluctuation degrees of all bisection solutions of the scheduling period by using the load data, and dividing the scheduling period into two time periods according to the scheduling period bisection solution with the fluctuation degree being the minimum; judging whether the number of the divided time periods is less than a preset number or not, executing a step S4 if the number of the divided time periods is less than the preset number, and otherwise, stopping division; S4, calculating fluctuation degrees of all bisection solutions of each time period by using the load data, and respectively determining a time period bisection solution with the fluctuation degree being the minimum corresponding to each time period; S5, determining a time period bisection solution with the fluctuation degree being relatively small; and S6, further dividing the corresponding time period into two time periods according to the time period bisection solution with the fluctuation degree being relative small, keeping the rest of the time period being unchanged, and returning back to the step S3.